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Hi,

This should not happen. Have you tried checking STOP_ON in RTC_CTRL_REG. If the RTC is ON this should be '1'. 

BACKUP should also be '1' as you have 2.5V on that pin. Does the backup voltage go low for a short period? You may want to continuously probe it when you remove VBAT.

Also, check what is MSECURE, this should be high for RTC to function.

Regards,

Gandhar.

Hi, Gandhar Dighe.

Very Thank you!

I found backup voltage is dropped when VBAT is removed.

If BKBAT is supplied by DC Power Supply, RTC backup function is OK.

But, We still don't have any idea for BKBAT's drop.

Regards,

Hi,

This is also a strange observation. What is the VBAT level and DC supply you use?

Can you provide the above levels with the corresponding BKBAT levels you see.

Regards,

Gandhar.

Hi

I meet similar situation now. I used ML414R as backup battery, which is rechargable. And find the RTC of some device didn't work when VBAT is "taken away". The BKBAT drop down to 1.2V for about 10ms. We set CFG_BOOT CK32K_LOWPWR_EN to 1, this can extend backup battery time, but cannot help the "abnormal" board.

The 32.768K crystal clock always run in full scale, amplitude is 800mV, when VBAT or BKBAT supply the crystal. Seems the RTC load is "large" to BKBAT(ML414R), that cause the "drop".  We add a 0.1uF capacitance on BKBAT, it helps little, BKBAT drop to 1.4V.

Is there any other register settings or  method to reduce the "inrush" current?

sincere

Elton Ye

Hi elton,

At 2.5V, ML414R is fully discharged then the observed dip is totally normal.

Default end of charge voltage in the PMIC backup battery charger is 2.5V. You need to change this value to 3.1V to fully charge ML414R.

End of charger threshold is configurable through  BB_CFG registers,  BBSEL bits.

Regards,

Alexis

Hi Alexis

Base on the TRM file of TPS65950, if I want use the RTC function which should be setting the STOP_RTC bit to 1.

But I also checked the Table 3-58 RTC_CTRL_REG, I saw the STOP_RTC bit was read only.

I have some confused on enable RTC function.

Would you please kindly tell me the correct enable step?

Thank you very much.

HI all:

We are using :

Processor : AM3703

PMIC : TPS65930

I'm testing RTC_backup battery!

We made secure to 1 ; so now it's in unsecure mode, all registers can be read/written!

But i'm unable to write any of the register,

And also checked default values are not proper as my knowledge!

RTC_CTRL_REG : 0x00 // RTC should be running : But it's not happening?

RTC_STATUS_REG : 0x00 // power reset should happen : But it's not happening?

RTC_INTERRUPTS_REG : 0x00

Can anyone please help me, what configuraiton i'm missing to make RTC working?

Regards,

santosh vastrad

santosh,

RTC_CTRL_REG bit 0 must be set to "1" to have the RTC running.

please refer to TPS65930 TRM

http://www.ti.com/litv/pdf/swcu052g

Regards,

Alexis

Hi Alexis,

Even i tried by wriitng in 1st bit for RTC to run,

then set the minutes register, but still i'm reading values 0 only!!!!!!!!!

suggest me write way of configuration for setting time and date for RTC?

Regards,

santosh vastrad

HI all:

I'm able to write into RTC registers now,

But not saw any type of updating Time registers,,,,,,,,,,,,,,,,,,,

So i'm near to solve the issue, please anyone tell me what's missing?

Regards,

santosh vastrad

Hello guys,

The issue is solved,

OOOps!

wrong register address used!

It 's working fine now!!!!!

Regards,

santosh vastrad